Ultra high frequency coupling system



July 19, 1949.- v G. HOLLINGSWORTH ETAL 2,476,732

ULTRA HIGH FREQUENCY COUPLING SYSTEM Filed Aug. 12, 1943 2 Sheets-Sheet l CONDUCTANCE STANDING WAVE RATIO SUSCEPTANCE.

Fig.1.

CONDUGTANCE Inventors 0 6 t v/ Ws e SU Mn r n Wo H s t m. Jt AA A Law w dM m PQNT o W y .w b G SUSCEPTANCE G. HOLLINGSWORTH ET AL 4 ,7

ULTRA HIGH FREQUENCY COUPLING SYSTEM July 19, 1949.

2 Sheets-Sheet 2 Filed Aug. 12, 1943 I Inventor-s.

' Guilfor-d. L. Hollingsworth,

' Nick A. Schuster', b W 6 JWZW Pig. 6.

Then" Attorney.

Patented July 19, 1949 UNITED "STATES ULTRA HIGH FREQUENCY GOUPISING SYST Guilford L. Hollingsworth and Nick-A. schilste fl,

Schenectady, N. ,Y., .assignorsto 'GcneraLElectric Company, a corporation of New York Application August12, 1943, Serial Nos-498332 (CL. ITS-44) 11 Claims.

Our inventionrelates to apparatus for couplin ultra-high frequency systems, andamore particularly, to apparatus for coupling'idieleetric Wave guides of the ho11ow-pipe type-withconcentric or coaxial transmission lines.

It is an object of our invention to provide-1a new and improved coupling device for ultra-high frequency systems.

It is anothenobjectof our. invention to provide a new and improved devicefor coupling a dielectric wave guideiof the hollow-pipe type to a coaxial or concentric transmission line.

For efficient transmission of energy from an ultra-high frequency electromagnetic wave .generator to utilization devicesinan-ultra-high frequency signalling system; it. is known thatwave guides of the hollow-pipe typeare preierredto concentric 'or coaxial cables aspa transmission means where the -.electromagnetic Waves are transmitted over an appreciable distance because of the considerably smaller: losses in such-wave guides. However, the :physicalrstructure -of-the usual type of ultra-high r frequency electromagnetic wave generator usually is ofv-such formthat energy is transmitted .therefrom'most easily 'loy means of a concentric or coaxial cable. Especiallywhere large amounts of such energyare being transmitted, it. is [desirable that the concentric :on coaxial connection to the generator be aszshort as possibleand-that the energy be transferred efiiciently to a wave guide-system without theintroduction of reflections due to abrupt admittance discontinuities in the transmission system.

Also in the construction of ultra-high frequency signalling systems which employ rotating apparatus, for example, a rotating antenna structure, it is known that, for simplicity of. mechanical structure,-a concentric or coaxial cable is to be preferred for transmittingthe ultraehigh frequency energy through a rotating joint, while for efiiciency of transmission a wave guide ofithe hollow-pipe type is preferablefor the transmission of energy through the remainder of the vsystem. Accordingly,.it,.is aiurther object of our invention to provide ,anew .and improved rotating coupling .un'it. tor anultra-high frequency system.

It is a stillJiurtheroob'ject.ofourinvention to provide a new and improved device for coupling a dielectric wave guidepf the hollow-pipe type to a coaxial or concentric-transmission line which is particularly adapted for transmitting large amounts of ultra ahighirequency energy.

"Still another object-cf our invention :is to .pro-

vide .amew, andiimnrov dzde ice iorc plin a dielectric wnreegnide of 1 thev -hollow-pipe, type to a coaxial or concentric transmission; line, which has-.awide b ndzpas chara t ristic, and whic requires; n .tunin adjustments- 2Brierl yest nzedi-ingacwrdame with our invent-ionultra f,gh- .frequencycenergyvi tran fi me moothIv:andefficient y from-an electroma net wave of the. :01" transverseelectromagnetic type bein -propa ated si ence-co x a o c centric transmissienli -n ztore waveof the TE 0r transverse electric 1 type for J propagation along a vetgnideee the=hel o m pet pe b m ans. f a .co lineunn tiinthe. iormof an exten i n the. inner qepndnctor cf the transmission line projecting, to theaoppcsitewall-of the Wave guide andhav ne-a contour; selected. to. match the, admittances ,;Of .:th wavec'ezuideuand (the transmi ion line.

For a better nderstamiinemf our invention, r f nc mavzbelhadito the. foll wing es riptio taken in connection with the accompanying drawi gsand i s.s en ll;be c nted ut in t e pp ndedcla i -Figalzillust at s a-p an-view o an emhodimentvof:v onriinventionzas app ed t a ystemzior-cm lll l a Q $B C wave gu de ef the hollowrpipatvpe and a eoncen rictransm s sion i es-Fi 2 -.is aim televat on view,..=pa-rt1y in section of the Jsystemr-QfaEig. 1 l-rsh w ngrrth positionioi.thee n lineid n eeitherein; ands-Fig. 3 is a side elevati nr-r ewi p t y in t ci/10 the system. Eiesi 1' and 51- are u v s; s o in certain .sharaet ristie :of the -;.syste of R es- ;Fiehfiisiaip an .v ew 91? qd ficat enmf th system shown infFig n Fig. 7; is-,a si de;elevation view, nart vzini non; fathesvstern l es 6. :Fia-' -showsutheqmanner in Whic -ou invention-mave applied to .a; syst m nt izin a rotating-cqnnlih bet een a: pa r of; p ra le W v uides:11andrlii t-&.is.-an en1areed; cross; sectiona viewptasn ntiomoi thezarf tan emen of Fi -'8.

. Referring mowzmcre :particularlyto R s. joint1y,:weah.a e=there; illustrated-our, inven o as pplied iito .-.an;.u1tra-hi;g.h= frequency: system pe uliar-1v: adapted: for transmitting mi rowaves and which may. QQmpI'iSQtaiidi lefitlicfWBJI'B guide I 0. of the hollows-pipe; type definedby conductive or =meta1lic 1,w'all :memhers defining therein va region throughcwhielr:electromagnetic waves are propagated. dielectricallyi andto which. ultrahigh frequency energy: is i-supplied rirom .a .axcoaxial transmissionilinez i l;ithe-.wtransvcrse electromagneticwavesof :the transmission-line. I It beingv convertedntoutransversez electric waves, in theiwave guide [0 by means of a coupling membe gli.

While it is to be appreciated that the principles of our invention are applicable to systems for controlling the propagation of electromagnetic waves of other types, we have chosen to represent our invention as applied to a system where TEol electromagnetic waves may be utilized.

The dielectric wave guide It) is shown'to be of the rectangular hollow-pipe type defined by a top wall 13, a bottom wall 14, and side walls l5, these walls preferably being formed of a suitable conducting material, such as copper or brass. The

wave guide [0, at its right-hand end, is closed by an end wall 16.

The concentric or coaxial transmission line it comprises a tubular outer conductor ll, prefer algly metallic in nature, and an inner conductor mechanically connected, as by soldering or welding, to the coupling member I2 which serves to maintain the inner conductor l8 coaxially aligned with respect to the outer conductor I! in a manner to be pointed out later. The outer conductor H is joined to the bottom wall 14 of the wave guide by means of a collar member I9 soldered or brazed to both the outer conductor and the bottom wall of the wave guide. The inner conductor 18 has a portion 20 of reduced diameter at its lower end which projects into a hole 2! in the end of the anode structure 22 of any suitable high frequency electron discharge device 23, such as a. magnetron. The anode structure 22 is sup ported by means of a glass seal 24 from a thin metal tube 25 brazed to theupper portion of a metallic tank or external wall structure of the electron discharge device 23. The inner diameter of tube 25 is made equal to'the inner diameter of tubular conductor l 7 so that the tube 25 functions as the outer conductor of a short section of coaxial transmission line connected to the device 23, the anode structure 22 forming the inner conductor of this short section of transmission line.

Disposed between the adjacent ends of conductors I! and 25 is a half-wave choke or connecting member 26 having a shoulder 25' at its upper end soldered or brazed to the lower end of conductor H and a pair of sleeves 2'1, 2? in concentric, spaced relation with conductor 25. A tubular sleeve 28, integral with the metallic tank of device 23, slips over the outer surface of member 26. The outer conductor l1 and member 25 are securely clamped to the tank of device 23 by means of a nut 28 engaging a thread on the outer surface of sleeve 28 and bearing against the upper surface of member 28.

The length of conductor 25 and each of the sleeves 27, 21' is made substantially equal to a quarter wave length of the high frequency wave supplied by device 23 so that these members function as a folded half-wave choke conductively connecting sections of the outer conductor of the transmission line, the points of high current density coinciding with the good electrical connections between conductor 25 and the metallic tank of device 23 and between the bottom of sleeve 21' and the aforesaid tank. In this folded half-wave choke the point of zero current occurs at the mechanical break or gap between members 25 and 26. The construction outline provides a rigidly supported inner conductor l8 which is capacitively coupled to the anode structure 22 by means of the portion 20 extending into the opening 2|. Hence, strains on the anode seal of the high frequency discharge tube employed are avoided.

The inner conductor I8 is electrically and The coupling member l2 comprises a metallic element extending from the upper end of the inner conductor 18 of coaxial line H to the opposite or upper wall l3 of the wave guide system. The member I2 is substantially circular in transverse cross section, the area of the cross section of the member increasing continuously and gradually from its point of connection with the inner conductor 18, where its size is the same as that of conductor l8, to its point of connection with the wall 3. The outer contour of the member i2 is in the form of a reverse curve and is constructed by spinning a shell of any suitable conducting material, such as copper or brass. The upper portion ofthe coupling member i2 is concave inwardly, while the lower portion, or the portion attached to the conductor i8, is concave outwardly, these two portions being separated by a point of inflection 29, i. e., a point where theslope of the reverse curve changes from a gradually decreasing value to a gradually increasing value.

In transmitting large amounts of energy from an ultra-high frequency generator to utilization devices, it has been found that extraction of energy from the high frequency devices is most easily obtained by means of a coupling loop attached to the end of a coaxial line. On the other hand, it has been found that transmission losses of the system are reduced when the high frequency energy is transmitted through a wave guide. The coaxial line of the Wave guide coupling, shown in Figs. 1-3 and described above, provides a means whereby high power may be efiiciently transmitted without corona or arcing at the point of conversion from the TEM or transverse electromagnetic waves propagated along the transmission line to the TE or transverse electric waves propagated along the wave guide system. In matching the impedance of the coaxial line to that of the wave guide system, it has been found that the diameter of the coupling unit I2 is a parameter which is useful for both matching the susceptance of the wave guide and the coaxial cable, as well as the conductance of these two members.

High frequency energy flows from the coaxial line H to the wave guide in in three directions. Thus, it flows forwardly, i. e., to the left in Figs. 1 and 2, into the wave guide l0 whose admittance is matched with the admittance of any utilization devices attached therewith. The flow of energy in this direction results in a constant conductance for the coupling unit l2 whose value is substantially independent of the position of the back wall it. Energy also flows sideways from the coupling unit l2 to the side walls l5 oi the wave guide. This flow of energy results in a constant susceptance for the coupling unit whose value likewise is substantially independent of the position of the back wall. The energy may likewise fiow in a third or final direction, namely, backwardly into the cavity between the unit and the ba-ck'wall l6. This energy excites this cavity to produce an apparent susceptance for the coupling unit which varies with the distance between the unit and the back wall according to the relation B=a' cot cl, where B is the value of susceptance, ,6 is a propagation constant having the value j A being the length of a wave in the guide, and l is the distance between the coupling'unit l2 and the :back: Wall. This iener yialso ip odlme n pparentcondu-ctancerwhicb: alsordepends upon this same distanceld When-:thisdistancez-Z. isapproximately-equal:toracuarter otawavelength of the wave propagatedalongtheguide .I'O; the susceptance. due to this -portion:.of;;theenergy division is;-equal torzero.v Also-,=..since.some.o the energy of'this excited cavity iscoupled into the matched wave guide: It; thehconductance of the guide is increased. The 'magn-itudei'oi'this increase is dependent upon the excitation'ofi-th'e' cavitytand increases as the backiwall distance deviates from multiples of a quarter'wave-length= of the high frequency wave.

In the curvesshownwin Edgar, the conductance and susceptance; of thercouplingrunit are plotted against-the distance of theb'ack .wall 'lli from the center of. the-couplingunit; The' curves of this figure show.:that'the admittance of the coupling unit may beadjusted to. a desiredvalue simply by changing. the spacing: of ab'a'ck wallwith respect to the coupling-unit; and-'thatapoint may be foundwhere, fora givenwave length' lg; the susceptancehasavalue of zero andthe conductance of the unit'imatches the conductanceof the wave uide- By meansi oi the' curvessh'owrr in' Fig. 5, there is illustrated-themanner in which theconductance' and susceptance of the coupling unit having a back wall position corresponding to the position 3il'and determined 'ln accordance with the manner outlined in the discussion of Fig. 4 vary with the wave-length of the energy transmitted along-the coaxial line l-l 'for propagation through the guide Ill; Curve 3'! shows-that the conductance increases :as -the' wave length of the transmitted wave is increased; while curve 32 shows that the susceptance of the unit changes from a positive to a negative-value as thewave'length is increased from a val-uelower than kg to a wave length greater than this value; Curve 33 illustrates the standing wave ratio'of 'voltage over a range of wave-lengths deviating from the desired operating wave length k From thiscurve it is evident that the Wave length may be varied over a range of-'- -5- per cent-of the desired operating wave length Ag without permitting the;standing wave ratio to reach a value greaterthan 1.4.

Referring againtoFigs. 1-3,. it'may be seen that the couplingunit I21 is provided with a flanged portion- 'at itszupper' endand an axially aligned hole-.36. The flange 35'. preferably is soldered to anupper wall l3itoinsure good electrical contact betweenthe coupling unit. I21. and the wave guide and, also, f'u'nctionsto. support rigidly the inner conductor. I8.- in a central position within outer conductor. IT. The axially aligned hole 36 which. extends likewise through inner conductor iBanditsextensionlO provides means wherebyair, or any other cooling agent may be blown into the anode structure 22 to assist in cooling this portion of the. high frequency electron discharge device utilized.

In the coaxially alignedwave guide coupling wave-guide Iii is provided with acurved back wall it is a-pproximately;v tangent. to? the curved back- Wall iii; the standing :wave-ratiopi; e., the ratio of the-voltage at failfiopfiffthel standing-wave in the 6' guide to the voltage at anode-ofthcwave;in the, uide it may be reducedand thaband pass of the system increased. To: further decreasethe' standing wave ratio in the'wave. guide I0; and to increase the band-pass of the coupling unit, m'etallic tuning diaphragms 38. areinsertedin-the guide is a calculated distance from the coupling unit l2, extending between the upper wall' l3 and lower wall I l and projecting into the wave guide it a distance sufii-cient to produce the susceptance necessary to reduce the standing wave ratio to a desired value, and to give the desired band" Bass. 7

In the arrangement shown in Fig; 8; high frequency electromagnetic waves in-a wave guideuiib are transmitted to a wave guide i through'a-rotating section of concentric transmission line.

The wave guide ill may supply high frequency" energy, for example, to a rotatable-antenna of a high frequency signalling system usedfor recognition purposes and the waveguide dl may be connected to a transmitter or areceiver. The waves being transmitted through the wave guides preferably are of the order of 10 centimeters. In such a high frequency signalling system,- since lower frequency waves are also sometimes employed for additional functions of the system, the construction shown permits the use of a 00- axial cable 32, also provided'with a-rotating sec tion to transmit the lower frequency waves from the stationary part of the apparatus to the rotating portions thereof. 7 g

The wave guide ll may be stationary and the wave guide ii? may be supported from a member'- 63 of the rotatable antenna structure, the member 53 being rigidly secured to a vertical shaft collar member 52' is attached to outer conductor 5i). A pair of semicircular grooved members 53; clamped together by means of screws- 54; serve to prevent separation of collar-members-EZ, 52'.

The coupling member l2, of atype similar tothe' coupling member described in connection with the coupling arrangement shown in Fig. 1, is con nected between theinner conductor 5| at its up per extremity and the upper wall of wave;

guide 4'5.

The connection between the Waveguide M and the inner conductor 5! is achieved by means of a similar coupling member l2. Likewise; a circular collar member 55 attached to the opening in the upper wall of wave guide-i! functions as alower section of the outer conductor of the coaxial cable.

In order to provide means whereby the outer conductor 5%! may be rotated with respect to the.

collar member 55, a capacitive coupling. joint is. interposed between these two sections of the outer conductor. Thus, the collar'member 55 is provided at its upper end'with'a portion 56 of enlarged inner diameter whichencircles, in spaced relation, the lower end of tubular outer conductor 5a; A' metallic sleeve 51 havinga length equal to a quarter wave length atthefrequency o'f'the the wave transmitted through the coaxial cable 50, is attached to the outer conductor 50 at a point spaced one quarter wave length from the lower end of the conductor 58. The length of the portion 56 is likewise made equal to a quarter wave length at the operating frequency and the inner diameter of the lower portion of the sleeve 51 is made equal to the inner diameter of the portion 56. Thus, from the construction as shown in Fig. 8, it is evident that there is a mechanical break between the conductor 50 and the conductor 55 and between the sleeve 5'! and the sleeve 56. These two mechanical breaks are spaced apart by a distance equal to a quarter wave length at the operating frequency. In this way, the sleeve 51 is connected by'soldering or brazing to tubular conductor 58 at a point of high current density to provide conduction of such current. The gap between the ends of members 58 and 5? occurs at a point of zero current on the line so that energy conduction in the tubular outer conductor of the coaxial line described is provided without the introduction of any objectionable refiections, as well as without the creation of any corona or electric discharge.

A tubular supporting member 59 is slipped over the collar '55 and provides means for supporting th stationary half of the race of the ball bearing 41. The rotating portion of the race is attached to tubular sleeve 68 mechanically connected to the shaft 64 at its lower end. The sleeve 6|! is secured to the sleeve 51 attached to tubular outer conductor 50 as previously described. A needle bearing SI is likewise provided between the members 59 and 86 to facilitate rotation therebetween and to assure proper alignment and spacing of the previously described electric connection between tubular conductor 59 and tubular collar 55.

In Fig. 9, we have shown in detail the construction of the rotatin joint in the inner conductor 5 I, as well as the manner in which the concentric or coaxial cable 42 is arranged within the conductor 5| for conveying signals or" lower frequency. Both coupling members l2, l2 are provided with axial holes through which the coaxial cable 22 is passed. The lower end of coupling unit |2 is joined to a sleeve member 64 having a portion 55 of reduced outer diameter, the length of the portion 65 being made equal to a quarter wave length at the frequency of the wave transmitted over the coaxial cable 58, 5|. A similar sleeve member 68 is secured to the upper end of the lower portion of tubular inner conductor 5!. The sleeve member 56 is likewise provided with a portion 61 of reduced outer diameter, the length of the portion 67 being made substantially equal to a quarter wave length at the operating frequency of the line. A tubular conductor 68 attached at its lower end tomember 66 and having a length substantially equal to a half wave length at the operating frequency of the line is in spaced relation with both the portions 55 and 61. By means of this construction, good electrical conductivity is provided between conductor 68 and sleeve 66 and between sleeve 54 and the coupling unit l2 at points of high current density. On the other hand, the mechanical break between the portions 55 and 6'! occurs at a point of zero current density and it is apparent, therefore, that continuous conduction of the high frequency currents through the tubular inner conductor of the coaxial line is provided without the introduction of any objectionable discontinuities to create standing waves on the transmission line.

The coaxial line 42' within the tubular inner conductor 5|. is enclosed within a metallic pipe ill of steel'or any suitable material which functions not only. to align and support the coaxial cable 42 within the tubular inner conductor 5|, but also conductively to connect the flexible metallic outer conductor 'H of cable 42 at its upper end with a connecting plug 72 and at its lower end with contact fingers I3. The connecting plug 72 is tubular in form and encloses a contact body M slotted in its opposite ends for engaging, at its lower end, the inner conductor 15 of line 42 and, at its upper end, the inner conductor 16 of a concentric line connected to communication or control circuits in the antenna structure.

At its lower end where the cable #2 passes through coupling member l2, the inner conductor of the coaxial cable 42 is provided with a contact member 18 which engages'the split fingers 19 at the upper end of a contact plug 80. Both the contact fingers i3 and the contact body are supported by'means of a pin 82 of insulating material within an end ring 83 attached by means of screws 33' to the bottom end of coupling member l2. A tubular support 84 re tained within the central hole of coupling unit I2 serves as means for supporting a bearing member 85 which rotatably engages a flanged bushing 86, secured, as by brazing, to the metal pipe 10.

In the operation of the rotating high frequency joints shown in'Figs. 8 and 9, as the shaft A l and the associated structure which it supports are rotated by any suitable driving means mechanically connected to gear 49, conductionof high frequency energy over the coaxial line comprising conductors 5! 5| is maintained through the capacitive joints of the inner and outer conduc tors thereof. The needle bearing arrangement a shown at the lower end of Fig. 8 assures alignment of the sections of the tubular outer conductor 50. The pipe l0, provided with a plurality of bearings 85 positioned between itself and the tubular inner conductor 5|, functions to maintain the inner conductor 5! coaxially aligned with the outer conductor 5Q. Continuous conduction between the rotatable sections of the inner and outer conductors of coaxial line 52 is secured through the contact finger arrangement shown in detail in the bottom of Fig. 9. Thus, it is seen that the tubular inner conductor -5| is stationary with respect to wave guide H throughout its length up to the mechanical break betweenconductor E8 and sleeve 64. On the other hand, the tubular outer conductor 50 and the concentric cable 42 with its supporting pipe 70 are rotatable. throughout the major portion of their length with respect to the wave guide i I Both coaxial lines are supported entirely by means of the conversion or coupling units l2, l2, thus avoiding the mechanical inconvenience of using auxiliary supporting devices. Such a structure permits the use of relatively small bearings for supporting the rotating antenna in a high frequency signalling system, as well as provides means for using a minimum length of coaxial lines to connect relatively rotatable sections of a wave guide system carrying large amounts of high frequency power.

It is thus seen that our conversion unit for coupling a concentric transmission line to a wave guide permits the transmission of large amounts of high frequency power without the arising of any objectionable comma or electric discharges, or objectionable;reflections and standing waves.

9 Because df'fihe I simple construction' of the unit, =it is easily attached o high 'freq'ue'ncy electric discharge ii'evices, a'nd is @150 es'pecially well adapte'd "for transmitting large amounts of high fr'equency'power btween rotating :units of a "high frequency signaliingsystem.

W11'i-le-we"-'haves' hown particular embodiments -'of our invention; train of course be understood that we do not wi'sh' to be lim'ited' thereto since various momfications niay be made, and=wecon- 'template byF-the appended-claims -to cover any 'suc'h modifications-as' autumn the true spirit and scopeof'omnnventim.

What *we claim-as=new and-"desire to secure by Letters Ratent-df thfinitedstates is:

1. In' a system 'for transni'itting-ultra-high ire- "quency electromagnetic-wavesfrom a concentric transmission line ito a dielectric wave guide of 'the-'hollow=pipe type, means? for converting trans- "verse electromagnetic Waves being propagated -'-a-long said transmission line to' transverse electric waves for propagation through said guide, 'said means "comprisinga metallic m mber extending across :said -guide and' eiectrically connectedbetweentl'reinnerconductor of said transmissionliriel andawail ofsa'id' guide, "said member being "substantially circular "in transverse cross "section "and *having'a transverse "diameter increasing "continuously "between the points of connection 6f"S2;id 60nfiuCtOTalid"sa.idWall to provide fa "contour 0f "the form of "a reversed "curve and of such dimensions that the susceptance "and conductanceo'fsaid guide "and said line are "matched over *a "broadband of frequencies wherebywavesfdfFfrequeniesinnaid band may be'transmittedb'etweenisaldfguideiand said line substantially withoutmehection.

2. In a systemrfor transmitting ultra-high frequency electromagnetic waves from a concentric transmission line "to a fdielectric wave guide of the hollow-pipe type, means forconverting transverse electromag-netic -:-waves being propagated along said'transmission line to transverse electric =wa-ves for propagation {through said guide, 7

said -'meanscomprising a 'n ietallic member extending across said "guide "and -eiectrically con- "n-ectedbetween the-inner conductor of said transmission line and a-wa-ll ofsaid' guide, said "memher being substantially circular in transverse cross "section, *the cross sectional diameter of said -rmember-increasing "continuously between the points of connection-"of sai'dconductor and said *wallft-heaverage-diameterof the 'cross section of said member'being greater thanthat of said inner conductor randrsuiiiciently large and of such shape as to match the susceptance and conductance of said transmissiondine whereby waves varying in frequency "ovena broad band of frequencies may be transmitted between said guide and said line substantially without reflection.

3. In combination, a dielectric wave guide of the hollow-pipe type, a concentric transmission line comprising a tubular outer conductor and an inner conductor, said outer conductor being electrically connected to said wave guide, and means for coupling said guide and said transmission line comprising a metallic member eX- tending across said wave guide transverse to the direction of propagation of waves therein and electrically connected between said inner conductor at its end adjacent said guide and the opposite inner wall of said guide, said member being substantially circular in transverse cross section, the area of the cross section of said member increasing continuously and gradually between its ;point of :connection :with @said inner conductor andits zpointiottconnection with said Wall. t o a 4. Incombination, .ashcllowwave guidaa concentric transmi'ssion :iline i' -proiecting from one side thereof and coupled -thereto,the-outer-conductor of i-said1linebeingzconductivelyiconnected to the adjacentwalhofmaideguideand the inner conductor of :said line iprojecting through -:said wall and being 'connectedaconductively to :the: opposite wall "of :said-Jgu-idefithesport-idn of :said intner conductor. projectingacrossssaid guide having a a continuously Yand'itrapidiy :increasing adiameter betweensaidwall's'ofisaictg uide.

5. ln aimiorowave signaliingrsystem, 'the .combination 1ofzfazrectangulartwauerguidetnf the hollow-pipe typega-scoa'xial tttansmissi'on line connected 1ther1ewith,'-:an"d :means zforitconverting the high ifrequency relectromagntic iawaves xtransvmitted'between said may guide rian'd saidline, said nieans comprising5a coupling member extending r across fsa'id guide and '.-ielectr=ically connected between the inner cor-iduotor of: said line and. theopposite wall or aidi'guide, said-member having a substantially ficircnlar transverse cross section continuously increasing Tin ima'gnitu'de from the size oftsaidiinnericonductor at its p int of connection therewith to 'ize at its p'ointof connection with *said We; ficiently -large'to match substantiallycompletely thef-rsusceptance and conductance df said wave g Ii-i'de.

6. -Ina system -"for trans"mittiiig iiltra highirequency electromagriti waves from a eoncentric t tending across saidg d'e and e1ectrica-lly*con- V nected" between the innercond tor-ofsaidtransmission'lineanda wall dies u-ide,-s'a-id'mem her-being substantiallycir'cular in transverse cross 's ection andmatirrgFa contourdif the form 1 of areversed-curve aiid 'includingapointof inilection, the diameterbf the cross sectlon of'said member between said point farfd' sa-id wall 'being suiiiciently larg'e t inat cfh' t e susceptances of said transmissionf'iine arfdsaid wave guide and the diameter of v the; cross section or ZSflfid I 'member between saidpoiritarfwsaid inner conductor being sumciently'sma'll tomatch theconductances of said waveguide and said transmissionline.

7. In .an ultra- -high':"frequency transmission system, "the combination or, ':a stationary wave guide, a 'rotating fwave i'guide, "a coaxial transmission line having andl'mer'jconfductor "and a tubular outer con'du'ctor"connectedbetween said wave guides,=-safd transmissiondine'having a'pair of rotatably supported sections, and high frequency energy coupling means connected between said inner conductor at its opposite ends and the walls of an associated one of said wave guides, said means comprising a metallic member substantially circular in transverse cross section, the area of the cross section thereof increasing gradually and continuously from the area of said inner conductor at its point of connection therewith to a value at its point of connection with the said wall of said wave guide suficiently large to match substantially completely the suspectance and conductance of said wave guide.

8. In a system for translating ultra-high frequency electromagnetic waves and lower frequency waves between two relatively movable por- 11 tions thereofjthecombination of a pair of wave guides of the hollowpipe type for transmitting ultra-high frequency waves, a first transmission line having a tubular inner conductor and a concentric outer conductor connectedbetween said wave guides, said transmission line comprising a pair'of adjacent sections supported for rotation with respect to'each other whereby said wave guides may be rotated with respect to each other, coupling means connected between said inner conductor at its opposite ends and a wall of the wave guide associated'therewith for converting th transverse electromagnetic waves propagated .along said transmission line to transverse electric waves for propagation along said wave guides, each of saidcoupling means having a hole therethrough concentricallyaligned with said inner conductor, and a second concentric transmission line for transmitting lower'frequency waves passingthrough said holes and said inner conductor, said second transmission line comprising a pair of adjacent sections. supported for rotation with respect to each other, each of said sections of said, second transmission line being mechanically connected to a corresponding section of said first, transmission line.

9. In an ultra-high frequency signalling system, an electron discharge'device having an output electrode, a dielectric wave guide of the hollow-pipe type, andmeans for transmitting energy from said electrode to said wave guide, said means comprising asection of concentric transmission line having an inner conductor, said conductor having one of its ends in spaced relation with and coupled to said electrode, and means for converting transverse electromagnetic waves being propagated along said lineto transverse electric waves for propagation through said guide, said last means comprising a metallic member extending across said guideand rigidly connected between said conductor at its other end and a wall of said guide to supportsaid conductor in said spaced relation with said electrode, said member increasing'continuously in transverse section between said conductor and-said wall of said guide and havinganaverage diameter greater than that of said inner conductor. A 7 v 10. In an ultra-high frequency signalling system, an electron discharge device having an output electrode, a dielectric wave guide of the hollow-pipe type, a concentric transmission line connected between said device and said wave guide, said transmission line comprising a tubular outer conductor and atubular inner conductor having one of its ends in spaced relation with said electrode and capacitively coupled thereto, and means for supporting said inner conductor in said spaced relation'jand for converting transverse electromagnetic waves being propagated along said transmission line to transverse electric waves for propagation through said wave guide, said means comprising a metallic member rigidly connected between said inner conductor at its other end and an inner wall of said wave guide, said member having a passage therethrough connected with said inner conductor for conveying cooling medium through said passage and said inner conductor to said electrode.

11. In an ultra-high frequency signalling system, an electron discharge device having an output electrode, a dielectric wave guide of the hollow-pipe type, a concentric transmission line connected between said device and said wave guide, said transmission line comprising a tubular outer conductor and a tubular inner conductor having one of its ends in spaced relation with said electrode and capacitively coupled thereto, and means'for supporting said inner conductor in said spaced relation and for converting transverse electromagnetic waves being propagated along said transmission line to transverse electric waves for propagation through said wave guide, said means comprising a metallic member rigidly connected between said inner conductor at its other end and an inner wall of said wave guide, said member having a substantially circular transverse cross section of continuously increasing diameter between its point of connection with said inner conductor and said inner wall and of sufficient size to match the susceptance and conductance of said wave guide, and an axial hole through said member connecting with said tubular inner conductor for conveying cooling medium through said inner conductor to said electrode.

GUILFORD L. HOLLINGSWOR'I'H. NICK A. SCI-IUS'I'ER.

REFERENCES CITED The following referenlces are of record in the 'file of this patent:

UNITED STATES PATENTS Number Name Date 2,064,585 Atienza Dec. 15, 1936 2,147,717 Schelkunofi Feb. 21, 1939 2,190,668 Llewellyn Feb. 20, 1940 2,223,224 Newhouse Nov. 26, 1940 2,257,783 Bowen Oct. 7, 1941 2,292,496 Von Baeyer Aug. 11, 1942 2,351,895 Allerding June 20, 1944 2,408,032 Beck Sept. 24, 1946 2,433,074 Tuller Dec. 23, 1947 2,434,925 Haxby Jan. 27, 1948 FOREIGN PATENTS Number Country Date 116,110 Australia Nov. 4, 1942 

